Systemic lupus erythematosus (SLE or lupus) is an important chronic disease in young women and this disease has served as a prototype for studying the interrelationships between immunologic diseases in the mother and fetal development. Pregnancy superimposed on lupus may alter the course of the illness. Conversely, the underlying disease or its treatment may affect the natural history of pregnancy. Pregnancy in a lupus patient is a relatively uncommon event and previous studies have been limited by small sample size, use of unvalidated measures of disease activity, or poorly defined pregnancy outcomes. This proposal will address these limitations in our knowledge of pregnancy outcome in these patients. The first study aim is to develop a lupus disease registry in Chicago. Patients will be recruited from different practice settings in order to obtain representative cases of disease in this geographic area. We plan to enroll 1650 patients in the registry which will be the largest SLE disease registry in the United States. The second study aim is to assess the effect of immunosuppressive drugs on pregnancy outcome in lupus patients using a retrospective case-control study design. A medical database pertinent to SLE and a validated pregnancy questionnaire will be completed on all female patients in the Chicago lupus registry. The American College of Obstetrics and Gynecology's standardized definitions of pregnancy outcome will be used. The third study aim will assess the relationship between disease activity and pregnancy using a prospective case-control study design. It is estimated that 60% of the women in the Chicago lupus registry will be in the childbearing years and eligible for this part of the study (n=640). Intensive data is collected when a registry patient is pregnant (becomes a case) or is selected as a non-pregnant control. Both cases and controls are evaluated at three month intervals for a total of 5 visits with a validated measure, the Systemic Lupus Activity Measure (SLAM). Disease activity (SLAM) from later visits will be compared to the initial visit SLAM. Since lupus is but one example of immunologically mediated disease, the impact of the findings of this proposed study may be generalizable to the large number of young women with related diseases who become pregnant each year in the United States. Thus this study can serve as a model for understanding maternal exposures such as immunosuppressive drugs and changes in maternal disease activity and their impact on pregnancy outcomes in other chronic diseases.